This invention relates to a veneer composer and clipper apparatus usable in the production of veneer sheets of predetermined width cut from a ribbon of veneer made up of veneer pieces of random width secured in edge-to-edge relationship. The apparatus is characterized by a number of features contributing to rapid operation with consistent accuracy in the width of the veneer sheets cut from the ribbon of veneer.
With the apparatus, and because of its speed of operation, and the accuracy in the cuts or clips produced, high production with minimum wastage is possible.
Veneer cut from a log results in a considerable amount of material in the form of veneer pieces of random width frequently having nonparallel opposite edges and including defective regions that should be trimmed from the pieces to produce a satisfactory product. In the production of plywood from such material, it has been the practice to process such pieces in apparatus known as a composer or welder, where the pieces are laid out side-by-side and the pieces then clipped or trimmed to remove defective areas and to produce veneer pieces having parallel opposite edges. Hot melt glue is then applied across the edges of the veneer pieces, and the pieces then pressed tightly against each other to form a continuous ribbon. Additionally, adhesive impregnated strings are applied across one of the faces of the ribbon so produced further to hold the veneer pieces securely to each other.
A veneer ribbon prepared as above generally described may be traveling from the region of the composer where the ribbon of veneer is consolidated while moving at a preselected line speed for the apparatus, with such movement subject to random stoppage at such times as waste is discarded or other events occur requiring that the assembled veneer ribbon stop its forward travel to enable other material to join with the ribbon to form a continuous piece.
In the production of plywood, the continuous ribbon of veneer produced in the composer is subjected to a final clipping operation as a clipper which cuts the ribbon of veneer into individual sheets having a size, i.e. width, conforming to that required by the plywood producer. To obtain maximum production, it is important that this clipper be capable of cutting "on the fly," i.e. without stopping movement of the continuous ribbon passing into the clipper. It is also important that the clipper be controlled in such a manner that a cut is produced only at such time as an exact amount of veneer has moved beyond the clipper, so as to produce a sheet of exact predetermined width when the cut is produced. With the conditions above described, the tracking of material traveling through the clipper must be accurately done, irrespective of stoppage in the movement of material and different time lapses when stoppages occur. Further, optimally, the control system should be accurate even with relatively rapid line speeds in the accumulator, if maximum production is to be obtained.
A general object of the invention is to provide a novel accumulator-clipper apparatus which is capable of producing rapidly and accurately veneer sheets of preselected edge-to-edge dimension from a veneer ribbon moving irregularly at line speed as above described.
As discussed above, in the making of a veneer ribbon in the accumulator, string or thread expanses are secured across one face of the forming veneer ribbon as part of the system holding the veneer pieces together. It is important that clipping be done in such a manner that complete cuts are produced. Following the invention, a rotary clipper is used to produce a cut, and the knife or blade making a cut moves first through the string expanses holding the veneer pieces together and then through the veneer, where such is backed by a back-up anvil roll. In this way, a complete and accurate cutting of the string expanses is assured.
A further feature and object is to provide, in apparatus as above described, roll surfaces in cooperating anvil and clipper rolls cooperating to provide a guide channel or throat guiding material for forward travel in intervals when cuts are not being performed.
A further object of the invention is to provide, in a composer-clipper apparatus, a control system which is relatively trouble free and easily maintained in operating order by the usual personnel provided to operate the equipment.